Variable volume pump or motor



Feb. 28, 1967 R ROBERTS 3,306,224

I VARIABLE VOLUME PUMP OR MOTOR Filed Oct. 8, 1964 3 Sheets-$heet l Feb. 28, 1967 R. w. ROBERTS 3,306,224

VARIABLE VOLUME PUMP OR MOTOR Filed Oct. 8, 1964 3 Sheets-Sheet 2 Feb. 28, 1967 R. w. ROBERTS VARIABLE VOLUME PUMP 0R MOTOR 3 Sheets-Sheet 3 Filed Oct. 19

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United States Patent Ofiiice 3,306,224 Patented Feb. 28, 1967 Illinois Filed Oct. 8, 1964, Ser. No. 402,590 3 Claims. (Cl. 103120) This invention relates to a variable volume pump or motor of the vane type.

It is the object of the present invention to provide an improved pump or motor of the balanced-vane type wherein a rotatable port plate is provided which enables the volume or displacement of the pump or motor to be smoothly varied between zero and full capacity without the necessity of rotating the entire pump chamber or changing the position of the rotor within the pump or motor.

Further objects and advantages of the present invention will be apparent from the following description, preference being had to the accompanying drawings wherein:

FIGURE 1 is an end view illustrating the displacement adjustment mechanism for the fluid pump or motor unit;

FIGURE 2 is an axial sectional view taken along the line 2-2 of FIGURE 1;

' FIGURE 3 is a sectional view taken along the line 33 of FIGURE 2 with the pump or motor unit illustrated at zero capacity;

FIGURE 4 is a view similar to FIGURE 3 with the pump or motor unit at full capacity, and

FIGURE 5 is a sectional view taken along line 5-5 of FIGURE 2.

Referring to FIGURE 2, the pump or motor of the present invention includes a casing 11 comprising end sections 12 and 13 separated by cam ring 14. The casing sections are bolted together by bolts 15. Journalled in the casing 11 is a rotor shaft 16 and a displacement adjusting shaft 17.

An adjustment mechanism 18 is provided for rotating the shaft 17. The adjustment mechanism 18 includes a bifurcated lever 19 which is secured to the shaft 17 by a bolt 20 and has a knob 21 with a threaded portion 22 thereon which is threaded into the end of the lever 19 at 23. A washer 24 is provided on the threaded portion 22. A slotted sector 25 is fixably mounted to the casing 11 and has a slot 26 therein to guide the lever 19 as it is rotated. The extension of the slot 26 is slightly less than 90.

The shaft 16 has a pilot portion 30 thereon received in a bearing 31. Journalled on the shaft 16 pilot portion 30 is a variable port plate 32 which is rotatable about the shaft 16.

The displacement control shaft 17 has a radially enlarged hub 33 formed thereon which is received in a recess 34 in the casing end section 12. A recess is provided in the hub 33 which receives the bearing 31 and pilot portion 30 of the shaft 16. One or more bolts 36 are secured to the hub 33 and engage in holes 37 in the port plate 32 to provide a driving connection between the shaft 17 and the port plate 32.

The shaft 16 is provided with a hub 40. The hub 40 has a plurality of radial slots 41 formed therein. Vanes 42 are slidably received in the radial slots 41. The vanes 42, as they rotate with the hub 40, engage an elliptical inner surface 43 provided in the cam ring 14. The rotor hub 40, vanes 42 and the surface 43 generally define two working chambers 45 and 46. Fluid chambers 45 and 46 are in radial symmetry on opposite sides of the axis of the rotor 40 and are always of equal volume. The rotor 40 is thus hydraulically balanced allowing the shaft 16 and rotor 40 to be easily supported within the end sections 11 and 12 of the casing.

The vanes 42, surface 43, rotor or hub 40, and end sections 12 and 13 define a plurality of fluid spaces 47 around the rotor 40 which vary in volume as the rotor rotates and as the vanes follow the contour of surface 43.

The casing section 13 includes the inlet and outlet passages for the pump or motor unit 10. Assuming the unit 10 is to be used as a pump the casing 11 includes a fluid inlet passage 50 and a fluid outlet passage 51 in end section 13. The fluid inlet passage 50 opens into fluid chamber 45 by means of an inlet port 52 and into fluid chamber 46 by means of an inlet port 53. Outlet passage 51 communicates with fluid chamber 45 through a port 55 and fluid chamber 46 through a port 54.

The rotatable port plate 32 is provided with elongated fluid recesses or ports 60 and 61 which will be rotatably positioned approximately opposite the fluid inlet ports 52 and 53. The rotatable port plate 32 is also provided with a pair of elongated recesses or ports 62 and 63 which will be rotatably positions approximately opposite the outlet ports 54 and 55.

Four venting ports or recesses are provided in the rotatable port plate in the area adjacent the base of the slots 41 in the hub 40. Venting ports 72 and 73 are provided for the high pressure or outlet ports 62 and 63 respectively. Venting ports or recesses 70 and 71 are provided for the inlet or low pressure ports 60 and 61 respectively. A plurality of fluid passages 74 are provided in the rotatable port plate 32 to interconnect each venting port with its corresponding pressure port. One or more connecting passages 74 interconnect each of the pressure ports with its respective venting port.

In FIGURE 3 the zero or minimum displacement condition of the pump or motor unit 10 is illustrated and in FIGURE 4 the maximum displacement condition of the unit 10 is illustrated.

The operation of the fluid pump or motor unit is as follows: by means of the lever 19 the shaft 17 may be rotated through an are slightly less than When a position of the lever 19 is selected the knob 21 may be turned to tighten the threaded portion in the lever 19 and securely hold the lever 19 to the sector 25.

Referring to FIGURE 4, assuming the unit 10 is to be used as a fluid pump, and assuming the shaft 16 is turning the hub 40 in the direction of the arrow in FIGURE 4, fluid will be drawn in through fluid inlets 52 and 53. The fluid inlets 52 and 53 are in communication with the ports 60 and 61 in the rotatable port plate 32 across the hub 40 through the spaces 47 between vanes 42. The hub 40 has recesses 65 formed therein in the areas between slots 41 to facilitate this communication.

Fluid will thus be conducted into the spaces 47 between the vanes for the entire length of the ports 60 and 61. Since the spaces 47 between the vanes are of increasing volume in the area opposite inlet ports 60 and 61 fluid will be drawn in from the inlets 52 and 53.

Ports 62 and 63 are in communication with fluid outlet ports 54 and 55 across the spaces 47 between the vanes. Since ports 62 and 63 are open to spaces 47 of decreasing volume between vanes 42 over their entire length, all the fluid drawn in at the inlet ports 52 and 53 will be pumped through outlet ports 54 and 55 as the rotor rotates. It will be seen then that in FIGURE 4 the maximum displacement of the unit 10 is illustrated with the inlet and outlet ports evenly spaced on either side of the major axis of the elliptical cam ring 14.

The pump or motor displacement may then be changed by rotation of the lever 19 and rotatable port plate 32 may be positioned as illustrated in FIGURE 3. The FIGURE 3 position illustrates the zero or minimum capacity .of the fluid pump or motor unit. It can be seen that the elongated inlet ports 60 and 61 in the rotatable port plate 32 are now exactly divided by the major axis of the cam ring 14. This then gives a condition wherein the elongated ports opposite the inlet ports 60 and 61 are immediately adjacent to an equal number of increasing and decreasing volume vane spaces 47. Since there are an equal number of increasing and decreasing spaces between the vanes opposite the inlet ports, no fluid can be pumped and the unit is at zero capacity.

A fluid venting system is provided to maintain the vanes 42 in a fluid balanced condition. When the pump is at zero capacity, for example as illustrated in FIGURE 3, high pressures can be developed in the area between the ports 61 and the ports 62. Due to the action of the venting system which allows fluid to pass freely between the elongated ports opposite the top portion of the vanes and the corresponding ports 70, 71, 72 and 73 at the base of the vanes the vanes will be in a fluid balanced condition. When excess pressure is encountered, as for example when crossing the area between ports 61 and 62 in FIGURE 3, the particular vane 42 involved can move down slightly and relieve the excess pressure to the outlet port 62. Relieving of excess pressure is accomplished by using square edge vanes as illustrated in the drawings wherein the excess pressure can get into the area between the end of the vanes and the surface 43 at the points between the ports 61 and 62, for example, due to the angle between the square edge of the vane and the surface 43.

Thus the unit if used as a pump can be varied anywhere between its maximum displacement and zero displacement by means of the manual adjustment mechanism 18. It will be apparent that other actuators may be used to rotate the port plate 32, for example, motor, hydraulic piston, or a rack and gear could be used to change the setting of port \plate 32.

The unit 10 can be used equally as well as a fluid motor, rather than a pump, having a displacement variable from zero to a maximum capacity. Due to the use of the venting system of the present invention, the vanes of the hydraulic unit are kept in a fluid balanced condition and thereby excess pressures which can be developed when the unit is at a Zero capacity setting are avoided.

From the above it will be apparent that applicant has provided a novel and simplified means for quickly and easily varying the fluid unit 10 from full displacement to zero displacement without the development of excessive fluid pressures. Further, by the use of an elliptical cam ring 14, the rotor is hydraulically balanced minimizing problems of supporting the rotor in the casing 11.

I wish it to be understood that my invention is not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention.

I claim:

1. A fluid pressure energy translating device including a casing, a rotor mounted within said casing, a cam ring surrounding the rotor, said rotor and cam ring defining a pair of fluid chambers, fluid pressure inlet and outlet means in said casing on one side of said rotor and communicating with each of said chambers, a plurality of vanes mounted in said rotor and engaging said cam ring to define a plurality of fluid spaces, a rotatable port plate mounted adjacent said rotor and on the opposite side therea hydraulic vane of with respect to said inlet and outlet means and rotatable with respect to said cam ring, said port plate having first elongated port in fluid communication with the inlet means having a plurality of fluid spaces, said port plate having a second elongated port in fluid communication with the outlet means and a plurality of fluid spaces, said elongated ports being of greater arcuate extent than said fluid inlet and outlet means whereby rotation of said port plate will simultaneously vary the effective length of said inlet and outlet means to thereby vary the fluid displacement of said device.

2. A fluid pressure energy translating device as claimed in claim 1 wherein said rotor includes recesses therein in the area between said vanes, said port plate having elongated port in fluid communication with each of said fluid inlet and outlet means through the spaces between said vanes, said recesses facilitating said fluid communication.

3. A fluid pressure energy translating device including a casing, a rotor mounted in said casing, a cam ring surrounding said rotor, said rotor and cam ring defining a pair of fluid chambers, fluid pressure inlet and outlet means in said casing for each of said chambers on one side of said rotor, a plurality of vanes slidably mounted in said rotor and engaging said cam ring to define a plurality of fluid spaces, a rotatable port plate mounted adjacent said rotor on the opposite side from said fluid inlet and outlet means and rotatable with respect to said cam ring, means mounted on said casing adapted to rotate said port plate and place said port plate in a selected position, locking means associated with said rotating means adapted to hold said port plate in a selected position, said port plate having a port in functional alignment with each of said fluid inlet and outlet means, each of said ports comprising an arcuate groove formed in said port plate and being in fluid communication with an inlet or outlet means through the spaces between said vanes, said ports being of greater arcuate extent than said inlet and outlet means and operable to place each of said fluid inlet and outlet means in fluid communication with a plurality of said spaces whereby rotation of said port plate by said rotating means will vary the displacement of said device, the displacement being variable between zero and a maximum.

References Cited by the Examiner UNITED STATES PATENTS 2,117,512 5/1938 Scott 103-120 2,335,284 11/1943 Kendrick 103-136 2,847,938 8/1958 Gondek. 3,103,893 9/1963 Henning et al 103-120 3,120,814 2/1964 Mueller 103-120 References Cited by the Applicant UNITED STATES PATENTS 2,711,698 6/1955 Bozek et a1. 2,827,857 3/ 1958 Eserkaln. 2,880,677 4/ 1959 Grupen.

DONLEY J. STOCKING, Primary Examiner.

MARK NEWMAN, MARTIN P. SCHWADRON,

Examiners W. L. FREEH, Assistant Examiner. 

1. A FLUID PRESSURE ENERGY TRANSLATING DEVICE INCLUDING A CASING, A ROTOR MOUNTED WITHIN SAID CASING, A CAM RING SURROUNDING THE ROTOR, SAID ROTOR AND CAM RING DEFINING A PAIR OF FLUID CHAMBERS, FLUID PRESSURE INLET AND OUTLET MEANS IN SAID CASING ON ONE SIDE OF SAID ROTOR AND COMMUNICATING WITH EACH OF SAID CHAMBERS, A PLURALITY OF VANES MOUNTED IN SAID ROTOR AND ENGAGING SAID CAM RING TO DEFINE A PLURALITY OF FLUID SPACES, A ROTATABLE PORT PLATE MOUNTED ADJACENT SAID ROTOR AND ON THE OPPOSITE SIDE THEREOF WITH RESPECT TO SAID INLET AND OUTLET MEANS AND ROTATABLE WITH RESPECT TO SAID CAM RING, SAID PORT PLATE HAVING FIRST ELONGATED PORT IN FLUID COMMUNICATION WITH THE INLET MEANS HAVING A PLURALITY OF FLUID SPACES, SAID PORT PLATE HAVING A SECOND ELONGATED PORT IN FLUID COMMUNICATION WITH THE OUTLET MEANS AND A PLURALITY OF FLUID SPACES, SAID ELONGATED PORTS BEING OF GREATER ARCUATE EXTENT THAN SAID FLUID INLET AND OUTLET MEANS WHEREBY ROTATION OF SAID PORT PLATE WILL SIMULTANEOUSLY VARY THE EFFECTIVE LENGTH OF SAID INLET AND OUTLET MEANS TO THEREBY VARY THE FLUID DISPLACEMENT OF SAID DEVICE. 